Pipe connecting device

ABSTRACT

A pipe connecting device designed for detachable, sealing assembly of two pipe ends which device consists of an outer part and an inner part inserted axially into the outer part and cooperating therewith for internal connection to the first pipe end. The cooperating contact surfaces of both the inner part and the outer part are conical in shaped. Furthermore, means are arranged to prevent axial movement between the conical contact surfaces.

TECHNICAL FIELD

The present invention relates to a sealing connecting device for joiningtwo pipe ends.

BACKGROUND ART

Connecting devices for sealing connection between two pipe ends havepreviously been used which have an internal diameter fitting the outerdiameter of one of the pipe ends and an external diameter fitting theinner diameter of the other pipe end. These seals must therefore bemanufactured with tolerances in relation to the diameters of the pipesto be joined, which means that very many seals must be available inorder to provide connections between pipe ends of varying diameters.

It is also known through U.S. Pat. No. 3,913,928, for instance, to useone and the same connecting device to join a pipe of a specific diameterto another pipe of a specific diameter, where this second pipe canassume one of two possible diameters. In this case the connecting deviceis provided with a collar that can be peeled back over the device sothat it assumes a larger outer diameter. This type of connecting devicemust also be manufactured with tolerances in relation to the pipes andmany devices are required to cover many ratios between diameters.

Also known through SE patent 9600828-9 (510 262) is a flexible nipple, aso-called combination nipple, by means of which a first pipe isconnected to a second pipe, the first pipe assuming one of two possiblediameters and the other pipe also assuming one of two possiblediameters. However, this type of connecting device must also bemanufactured with tolerances to enable connection to specific pipediameters. One variant of said combination nipple is manufactured, forinstance, under the designation 75-70/50-40 and another under thedesignation 64-58/50-40 signifying D1-D2/d1-d2 which means D1 or D2connected to d1 or d2.

Difficulties are thus encountered with these known connecting devices injoining a first pipe to a second pipe, using the same connecting device,where the diameter of one of the pipes is permitted to lie within aninterval rather than having a specific value. It also is difficult toobtain a tight connection to a pipe end that is not entirely circular.

OBJECT OF THE INVENTION

The object of the present invention is to solve the above problems andto provide a pipe connecting device for a sealing fit between two pipeends, which device enables stepless adaptation of the device within aninterval of pipe diameters.

Another object of the present invention is in a better way thanpreviously to achieve a tight seal between two pipe ends by expanding apipe connecting device towards the inner surface of a pipe end.

The object of the present invention is also to achieve a tight seal to apipe end that is not entirely circular, i.e. may be slightly oval.

SUMMARY OF THE INVENTION

The above objects are fulfilled by means of the present invention asrevealed in the characterizing parts of the claims, and said drawbacksare eliminated.

The invention relates to a pipe connecting device designed fordetachable, sealing assembly of two pipe ends. The device consists of aninner part and an outer part co-operating with the inner part forinternal connection to one of the pipe ends. The co-operating contactsurfaces of the inner part and the outer part are conical in shape.Means are also arranged to prevent axial movement between the conicalcontact surfaces. These means preferably comprise the two conicalcontact surfaces being provided with a co-operating thread profilehaving trapezoidal shape, for instance.

Two pipe ends are joined by inserting one end of the inner part axiallyinto the outer part of the connecting device. Thereafter the outer partof the connecting device is inserted into the first pipe end, whereafterthe inner part is pressed, e.g. screwed into the outer part in order toexpand the outer part towards the inner surface of the first pipe end. Asecond pipe end is then connected in a first embodiment to the other endof the inner part which is designed, e.g. with a lip ring seal in asealing groove, to take the pipe end.

In a second embodiment the outer part is provided with an inner sealingsleeve rigidly attached to the outer part, against which sleeve an innerpipe end, i.e. with smaller diameter, seals when the inner part of theconnecting device is pressed down into a narrowing space between theouter part and its rigidly attached sealing sleeve by means of ascrewing movement, for instance.

Within the scope of the invention the other end of the inner part mayalso be provided with a corresponding outer part having mutuallyco-operating conically threaded contact surfaces for internal connectionto a second pipe end. The inner part may also be bent in order to joinpipe ends whose axes are not parallel. The means preventing axialmovement between inner and outer parts may also be in the form ofexternal clamping means or, quite simply, may consist of a glue joint.

The pipe connecting device in accordance with the invention ispreferably used when joining waste pipes in joists or in concrete. Themain area of application for pipe connecting devices in accordance withthe invention is when connecting a new waste pipe in an existing wastepipe made of cast iron. These old waste pipes often vary considerably indimension.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to theaccompanying drawings.

FIG. 1 shows an end view of a pipe connecting device in accordance withthe present invention.

FIG. 2 shows an enlargement of a section alone the line A-A through thepipe connecting device in FIG. 1, with the addition of two pipe ends.

FIG. 3 shows an outer part of the pipe connecting device in accordancewith the invention, and a detail of the surface of the outer part.

FIG. 4 shows a section B-B through the part shown in FIG. 3.

FIG. 5 shows a section corresponding to FIG. 2 in accordance with asecond embodiment of the present invention.

DESCRIPTION OF THE INVENTION

FIG. 1 shows an end view of a pipe connecting device 1 for joining afirst pipe end 2 to a second pipe end 3. The second pipe end 3 isinserted axially into an inner part 4 of the pipe connecting device 1.The inner part 4 is also provided with a key handle 5 intended forturning the inner part 4 in relation to an outer part 6 of the pipeconnecting device.

FIG. 2 shows the pipe connecting device in an axial section, the secondpipe end 3 being inserted in a neck portion 7 of the inner part 4 of thepipe connecting device. The neck portion is provided with a sealinggroove 8 in which a lip seal 9 is situated, constituting a gas seal forslight pressure in the direction of the first pipe end. The inner partof the pipe connecting device is provided at the other end with aconical outer surface 10 a, narrowing towards the bottom, which isprovided with a trapezoidal thread 11. The surface 10 a terminates in anannular central flange 12, towards the middle of the inner part.

An outer part 14, provided with an annular end flange 13, is alsoarranged having a conical inner surface 10 b co-operating with theconical outer surface 10 a of the inner part. The conical inner surface10 b of the outer part is also provided with trapezoidal threadingcorresponding to the inner part. The cylindrical outer surface 15 of theouter part abuts directly, or indirectly as shown in FIG. 2, against thefirst pipe end 2. The inner part is also provided with an internallynarrowing neck portion 16 arranged so that one inner diameter of theinner part is the same as the inner diameter of the other pipe end 3.

The function of this construction is that screwing the inner part 4 intothe outer part 14 causes the outer part to expand steplessly radially,whereupon the connecting diameter of the outer part can be varied withinan interval. This expansion also equalises any ovalness in the pipe end.

FIG. 3 shows the outer part 14 which, according to the presentembodiment, consists of a primary part 17 and a secondary part 18 withone end concentrically connected to one end of the primary part. Thefigure also shows, partly enlarged, that the outer surface of theprimary part 17 is provided with wedge-shaped sealing rings 19. Theinner surface of the secondary part 18 is also provided withwedge-shaped sealing rings.

FIG. 4 shows the primary part 17 of the outer part enlarged in an axialsection which clearly shows the inner conical surface 10 b of the outerpart, provided with trapezoidal threading. Its outer surface also showsthe wedge-shaped sealing rings 19. The figure also shows thewedge-shaped sealing rings 20 on the inner surface of the secondary part18. The primary part 17 passes via a breaking ring 21 to the secondarypart 18. The secondary part 18 has an inner diameter that is equal, orsubstantially equal, to the outer diameter of the primary part 17. Thesecondary part 18 also has an outer diameter that is greater than theouter diameter of the primary part 17. The secondary part 18 is thusintended to be folded back over the primary part in order to achieve anexpansion interval with larger diameter. The secondary part can easilybe removed by cutting it off in order to adapt the connection to anexpansion interval with smaller diameter. This design of the outer partenables stepless connection of the outer part to the other pipe end inan interval of inner diameters between a minimum corresponding to theouter diameter of the primary part of the outer part at rest, and amaximum corresponding to the secondary part of the outer part expanded.The outer part can thus be used for two diameter intervals which overlapeach other, i.e. 65-75 mm and 73-83 mm.

To connect a first pipe end 2 to a second pipe end 3, the inner part 4is first screwed about half way into the outer part 14, after which theinner part, together with the outer part, is introduced into the firstpipe end 2. Thereafter, the outer part 14 is expanded towards the innersurface of the pipe end 2 by the inner part 4 being screwed further intothe outer part 14. The second pipe end 3 is then inserted into the otherend of the inner part, past the lip seal 9 and the connection is thencomplete. Alternatively, the second pipe end 3 is inserted into theother end of the inner part 4 before the outer part 14 is inserted andexpanded. The method used is dependent on how flexible the pipes are.After assembly, it is the expanded side of the pipe connection which isthe most fixed connection, whereas the pipe that is inserted past thelip seal can be displaced axially.

FIG. 5 shows a second embodiment of the invention in which the pipeconnecting device 1 is arranged, in similar manner to that describedabove, so that its outer surface 15 connects with the first pipe end 2with large diameter, and the pipe connecting device is also providedwith an inner sealing sleeve 51 to connect with the second pipe end 3.The inner sealing sleeve 51 is rigidly joined to the outer part 54 ofthe pipe connecting device so that a conical space 55 is formed in theouter part. As described above the outer surface of the outer part isexpanded towards the inner surface of the first pipe end when the innerpart 4 of the pipe connecting device is pressed, e.g. screwed, down intothe outer part 54. The inner sealing sleeve 51 is simultaneously pressedinwardly towards the second pipe end 3. A tight joint has thus beenachieved between two pipe parts 2, 3 of different diameters.

1. A pipe connecting device (1) designed for detachable, sealingassembly of two pipe ends (2, 3), which device consists of an outer part(14, 54) and an inner part (4) inserted axially into the outer part (14,54) and co-operating therewith, which inner part (4) on its insidedirect or indirect is connected to the first pipe end (3), theco-operating contact surfaces (10 a, 10 b) of both the inner part (4)and the outer part (14, 54) being conical in shape, and means (11) beingarranged to prevent axial movement between the conical contact surfaces(10 a, 10 b), that the means (11) preventing axial movement comprise thetwo conical contact surfaces (10 a, 10 b) being provided with aco-operating thread profile, characterized in that the outer part (14,54) is arranged to expand radially to internal attachment towards theother pipe end (2) by screwing the inner part (4) into the outer part(14, 54).
 2. A pipe connecting device as claimed in claim 1,characterized in that the device accommodates pipe ends (2, 3) ofdifferent diameters and that the pipe end (3) with the smallest diameteris arranged to be connected internally to the inner part (4) and thepipe end (2) with the largest diameter is arranged to be connectedexternally to the outer part (14).
 3. A pipe connecting device asclaimed in claim 2, characterized in that the thread profile istrapezoidal in appearance.
 4. A pipe connecting device as claimed inclaim 1, characterized in that the device is designed for connection topipe ends (2, 3) with parallel central axes.
 5. A pipe connecting deviceas claimed in claim 1, characterized in that the outer part (14)comprises a primary part (17) and a secondary part (18), one end ofwhich is concentrically connected via a breaking ring (21) to one end ofthe primary part (17).
 6. A pipe connecting device as claimed in claim5, characterized in that the outer diameter of the primary part (17) issmaller than the outer diameter of the secondary part (18).
 7. A pipeconnecting device as claimed in claim 6, characterized in that the innerdiameter of the secondary part (18) is the same size as the outerdiameter of the primary part (17).
 8. A pipe connecting device asclaimed in claim 5, characterized in that the outer surface of theprimary part (17) and the inner surface of the secondary part (18) areboth provided with wedge-shaped sealing rings (19, 20).
 9. A pipeconnecting device as claimed in claim 1, characterized in that the outerpart (54) of the device is provided with an inner sealing sleeve (51) sothat a conical space (55) co-operating with the inner part (4) issituated between the sealing sleeve (51) and the cuter surface (15) ofthe outer part (54).